Tube bender



Aug. 28, 1962 G. E. FRANCK TUBE BENDER Filed Jan. 5, 1960 United StatesPatent 3,051,218 TUBE BENDER George E. Franck, Riverside, 111., assignorto Imperial- Eastman Corporation, a corporation of Illinois Filed Jan.5, 1960, Ser. No. 540 Claims. (Cl. 153-46) This invention relates totube benders and in particular to manually operable tube benders.

A conventional form of manually operable tube bender is one including amandrel having a peripheral bendforming groove and provided with anoperating handle. Means for pressing the tube into the mandrel grooveare associated with the mandrel, said means conventionally comprising ashoe having a groove defining a tube pressing surface. The presentinvention is concerned with a new and improved means for connecting theshoe to the mandrel for movement of the shoe in a path circumjacent thegroove and with the pressing surface confronting the mandrel groove tourge the tube into the mandrel groove during such movement.

It is, therefore, a principal object of the present invention to providea new and improved tube bender.

Another object of the invention is to provide such a tube benderincluding connecting means permitting movement of the shoe outwardlyfrom an annular tube pressing path at only one point in said path andmaintaining the shoe in that path at all other points therein.

A further object is to provide such a tube bender wherein the connectionmeans includes a first portion permitting movement of the shoe outwardlyfrom the path at only two points in the path and maintaining the shoeagainst the tube bending forces generated at all other points therein,and a second portion precluding movement of the shoe outwardly from thePath at one of said points.

Another object is to provide such a tube bander wherein the point inwhich the shoe is permitted to move outwardly from the path correspondsto the starting point of the bend.

Other features and advantages of the invention will be apparent from thefollowing description taken in connection with the accompanying drawingwherein:

FIG. 1 is a fragmentary elevation of a tube bender embodying theinvention, with the shoe spaced from the mandrel to permit insertion ofa tube portion therebetween;

FIG. 2 is a View generally similar to that of FIG. 1 but with the shoeand mandrel brought together to effect initiation of a bend in the tubeportion;

FIG. 3 is a view generally similar to that of FIG. 2, but with the shoedisposed as at the completion of a 90 degree bend in the tube portion;

FIG. 4 is a View generally similar to that of FIG. 3, but with the shoedisposed as at the completion of a 180 degree bend of the tube portion;and

FIG. 5 is a transverse section taken substantially along the line 5-5 ofFIG. 4.

In the exemplary embodiment as disclosed in the drawing, a tube bendergenerally designated is shown to comprise a mandrel 11 to which issecured a handle 12 and a tube holding hook 13 of conventionalconstruction. A tube pressing shoe 14, provided with a handle 15, isassociated with mandrel 11 by a connecting means generally designated 16whereby a pressing surface defined by an elongate groove 17 in the shoe14 may move in an annular path circumjacent an outwardly opening,annular groove 18 in the periphery 19 of the mandrel. As the shoe movesalong the periphery 19, it forces the tube T, which is held againstlongitudinal movement by hook 13, into the groove 18 thereby forming thedesired bend therein.

3,@5l,2l3 Patented Aug. 28, 1962 "ice In order to insert the tube Tbetween the mandrel and shoe at the beginning of the bending operationand to permit the removal of the bent tube from the mandrel groove uponcompletion of the bending operation, it is desirable that the shoe beselectably movable outwardly from its annular path of movement aroundthe periphery of the mandrel. Connecting means 16 herein is arranged toprovide both the annular movement of the shoe along the pathcircumjacent the mandrel groove and the desirable outward displacementof the shoe permitting such insertion and removal of the tube.Connecting means 16 provides such desirable functioning in an improvedfoolproof manner.

More specifically, connecting means 16 comprises a pair of arms 20extending from shoe 14 to adjacent the opposite sides of mandrel 11adjacent its axis 21. Each arm 24 is provided with a hole 22 including apivot portion defined by a circular are 23 extending at least degreesbut less than 360 degrees, and a recess 24 defined by a rectangleextending radially outwardly from the opposed ends of the are 23. A post25 is secured coaxially to mandrel 11 and includes ends 26 projectinglaterally from the opposite sides of the mandrel and through opening 22in each of the arms 20. The transverse seetion of each of ends 26includes a rectangular portion 27 having a width corresponding to thewidth of recess portion 24 and opposite segmentally cylindrical endportions 28 concentric of axis 21 and having 'a radius corresponding tothe radius of arc 23. Post 25 is further provided with a round head 2%at one end and a threaded portion 30 at the other end on which a nut 31is threaded to act through a Washer 32 in securing the post to themandrel.

The portion of connecting means 16 defined by hole 22 and post 25partially provides the desirable functioning discussed above. Morespecifically, the direction of elongation of the rectangular portion 27of post end 26 is made to be perpendicular to the longitudinal extent oftube T when it is disposed in the mandrel groove 18 and held therein byhook 13 preparatory to forming a bend therein. Further, the direction oflongation of rectangular portion 24 of hole 22 is made to beperpendicular to the longitudinal extent of the elongated groove 17 inshoe 14. Thus as best seen in FIG. 1, when shoe 14 and mandrel 11 aredisposed with post end 26 in rectangular inner portion 24 of hole 22,the shoe is spaced substantially outwardly from periphery 19 of themandrel In this arrangement, arcuate portion 23 is disposed between post25 and the starting point 33 of the bend to be formed in tube T, andtube T may be readily inserted into groove 18 between shoe 14 andmandrel 11 to extend tangent to groove 18 at starting point 33. Afterthe tube has been thusly inserted, as shown in FIG. 2, the shoe 14 maybe brought toward mandrel periphery 19 to engage surface 17 of the shoewith the wall of tube T and urge it fully into groove 18. In thisposition, post end 26 is disposed in the arcuate portion of opening 22.In this arrangement, arm 20 may pivot on post end 26 whereby shoe 14moves along mandrel periphery 19, as to the position of FIG. 3, pressingthe tube T into groove 18 as it moves therealong to form the desiredbend therein.

Once shoe 14 leaves the starting position 33 the direction of elongationof rectangular portion 24 of arm hole 22 is disaligned with thedirection of elongation of the rectangular post portion 27, therebypreventing outward displacement of the shoe relative to the periphery 19of the mandrel. Thus, the shoe is retained in the desired annular pathcircumjacent groove 18 notwithstanding the development of substantialforces between the shoe and mandrel during the bending operation. Thisdesirable circumjacent retention of the shoe is maintained over a full180 degree movement of the shoe about the mandrel periphery. However,when the shoe reaches the 180 degree position 34 as shown in FIG. 4,rectangular portion 24 of opening 22 becomes again aligned with therectangular portion 27 of post end 26. Connecting means 16 furtherincludes a' second portion which precludes movement of shoe 14 outwardlyfrom mandrel periphery 19 in this 180 degree position.

More specifically, the second portion of connecting means 16 comprises apin 35 on each arm extending parallel to axis 21 and projecting into anannular groove 36 in each of the opposite faces of mandrel 11 andextending concentrically of axis 21. A channel 37 extends radiallyoutwardly from each groove 36 adjacent bend starting point 33. When shoe14 is disposed at starting point 33, pin is aligned with channel 37 andmay move outwardly therethrough (away from axis 21) to permit thedesired spacing of shoe 14 from mandrel periphery 19, as best seen inFIG. 1. When shoe 14 is moved into engagement with the tube T, as shownin FIG. 2, the pin 35 becomes disposed in annular groove 36 wherein itmay move freely through the annular path defined by groove 36, as to thepositions of FIG. 3 and FIG. 4. It should be noted that in the positionof FIG. 4, pin 35 precludes the outward movement of shoe 14notwithstanding the alignment of hole portion 24 with rectangularportion 27 of the post 26. Resultingly, outward spacing of shoe 14relative to mandrel periphery 19 may be effected only at a singleposition wherein the shoe is at the bend starting point 33, positivelyprecluding inadvertent spacing of the shoe from the mandrel at all otherpositions to assure an improved accurate bend in the tube T and preventinadvertent damage to the tool as might occur if the post end 26 were tobe disposed even partially within opening portion 24 when the userattempts to return the shoe to the starting position from the 180 degreeposition illustrated in FIG. 4.

To facilitate bending of tube T, handle 15 may be connected to shoe 14by means of a two-position connection structure generally designated 38'permitting handle 15 to be moved to a position at right angles to theposition as shown in FIG. 3, whereby the shoe 14 may be moved from theposition of FIG. 3 to the position of FIG. 4

without a crossing of handle 12 by handle 15 during this operation. Amore detailed description of structure 38 is set forth in my copendingapplication, Serial No. 804,256, now Patent No. 2,979,976. Arm 20 mayfurther be provided with an opening 39 cooperating with an angle scaleon mandrel 11 to indicate the degree of bend effected by the tool 10.

In using tool 10, a workman firstly arranges the tool as illustrated inFIG. 1 with shoe 14 spaced outwardly from the mandrel periphery 19 atbend starting point 33. This outward spacing is permitted by themovement of pin 35 through the channel 37 and the movement of hole 22outwardly to receive the post end 26 in hole portion 24. Tube T is theninserted between the groove surface 17 and mandrel groove 18 and book 13is engaged with the tube to hold the tube in association with themandrel. The shoe 14 is next brought into engagement with the outersurface of tube T by movement of arm 20 downwardly as' seen in FIG. 2 todispose pin 35 in annular groove 36 and to receive post end 26 inarcuate portion 23 of opening 22.

The bending of tube T is then effected in a substantially conventionalmanner by urging handle 15 in a clockwise direction as seen in FIGS. 2,3 and 4 toward handle 12 until shoe 14 has moved along groove 18 thepreselected angular amount. The shoe 14 is maintained in the annularpath circumjacent groove 18 in all angular positions away from startingpoint 33 during such bending of the tube T.

Upon completion of the desired bend, handle 15 is reversely swung tomove shoe 14back to the starting point 4 33. The shoe 14 is now movedoutwardly from engagement with the bent tube T to the position ofFIG. 1. Hook 13 is then disengaged from tube T permitting the tube to bedisengaged from the tool.

While I have shown and described one embodiment of my invention, it isto be understood that it is capable of many modifications. Changes,therefore, in the construction and arrangement may be made withoutdeparting from the spirit and scope of the invention as defined in theappended claims.

I claim:

1. A tube bender comprising: a mandrel having a peripheral bend-forminggroove having a bend-start point; a shoe having a tube-pressing surface;and means connecting the shoe to the mandrel for movement of the shoe ina path circumjacent said groove away from said bendstart point and withsaid surface confronting the groove to urge a tube into the grooveduring such movement, said connecting means including an arm extendingfrom the shoe, a pin on one of said mandrel and arm extendingtransversely to the central plane of said groove, and a pin receivinggroove in the other of said mandrel and arm having an annular portionand a straight portion extending outwardly from the annular portionsubstantially in alignment with said bend-start point, a post on one ofsaid mandrel and arm and a hole in the other of said mandrel and arm,the one of the post and hole on said mandrel being at the axis of saidbend-forming groove, said hole having a pivot portion and a recessportion extending radially outwardly from the pivot portion, the postand recess portion being complementary to permit movement of the shoeoutwardly from said path only at the bendstart point and therefrom andmaintaining the shoe in said path at all other points along said path.

2. The tube bender of claim 1 wherein the cross-section of said pivotportion in a plane perpendicular to the mandrel groove axis is definedby a circular are extending more than 180 and less than 360", thecross-section of said recess portion in said plane is defined by arectangle extending outwardly from between the ends of the arc, and thecross-section of the post in said plane is defined by a rectangularmid-portion having a Width corresponding to the width of said recessportion of the hole to permit movement of said post into and from saidrecess portion when desired, said cross-section of the post in saidplane further being defined by segmentally circular end portionsconcentric with said mid-portion and having a radius corresponding tothe radius of said are to permit pivoting of said post in said pivotportion of the hole when desired.

3. A tube bender comprising: a mandrel having a peripheral, annularbend-forming groove; a shoe having a tube-pressing surface; and meansconnecting the shoe to the mandrel for movement of the shoe in a pathcircumjacent said groove and with said surface confronting the groove tourge a tube into the groove during such movement, said connecting meansincluding an arm on the shoe provided with a hole having a pivot portionhaving a circular cross-section and a recess portion extending radiallyfrom the pivot portion, a cylindrical post axially of the mandrel andextending through said hole, said post being arranged to be received insaid recess portion in only two positions, a pin on one of said mandreland shoe arm extending transversely to the central plane of said groove,and a guide groove in the other of said mandrel and shoe arm having anannular portion and an outwardly extending portion at one point in theannular portion, said pin being laterally slidably fitted in the guidegroove permitting movement of the shoe outwardly from said path at onlyone point in said path corresponding to one of said post positions, thecross sectional area of the pin being smaller than the cross sectionalarea of the post. a

4. The tube bender of claim 3 wherein said one point in the path ofmovement of the shoe comprises a point in the bend-forming groove atwhich the bend is initiated.

5. A tube bender comprising: a mandrel having a peripheral annularbend-forming groove extending at least approximately 180; a shoe havinga tube-pressing surface; and means connecting the shoe to the mandrelfor movement of the shoe in a path oircumjacent said groove and withsaid surface confronting the groove to urge a tube into the grooveduring such movement, said connecting means including a first portionarranged to permit movement of the shoe outwardly from said path at onlytwo, 180 spaced points in said path and maintain said shoe in said pathagainst the tube-bending forces generated at all other points therein,and a control portion arranged to permit movement of :the shoe outwardlyfrom said path at only one of said points, said control portion beingsubstantially less capable than said first portion of resisting forcessuch as the tube-bending forces, said one point comprising the startingpoint of the bend.

References Cited in the file of this patent UNITED STATES PATENTS462,538 Doyle Nov. 3, 1891 2,678,573 Taylor May 18, 1954 10 2,831,382Klamm Apr. 22, 1958 FOREIGN PATENTS 454,731 Canada Feb. 22, 1949 459,694Canada Sept. 13, 1949

